PREPARATION OF ACTIVATED CARBONS FROM BANANA LEAVES BY CHEMICAL ACTIVATION WITH PHOSPHORIC ACID. ADSORPTION OF METHYLENE BLUE

Banana leaves, which represent the second major residue generated in banana cultivations, were used as raw material for the preparation of six different activated carbons. The adsorbents were developed from this lignocellulosic precursor by means of chemical activation with phosphoric acid, modifying the concentration of the activating agent and the carbonization temperature during the production process. The obtained activated carbons presented slightly acid points of zero charge, high specific surface areas (798.51-1227.60 m(2)/g) and large total pore volumes (0.831.29 cm(3)/g), resulting mainly mesoporous. These adsorbents were employed for the adsorption of Methylene Blue in batch process. The dynamic experimental data were adjusted to pseudo-first and pseudo-second order kinetic models by non-linear regression, while the equilibrium experimental data were correlated to the Freundlich and Langmuir models. The monolayer adsorption capacities of this dye reached significant values, between 19.08 and 48.01 mg/g.